Background As an alternative to vitamin K antagonist and low-dose aspirin (< 325 mg), non-vitamin K oral anticoagulants are available for the prevention of stroke in patients with atrial fibrillation. However, the mortality risk associated with these drugs in daily practice remains unclear. Objective To evaluate the risk of all-cause mortality associated with non-Vitamin K antagonist oral anticoagulants, vitamin K antagonists or aspirin in patients with atrial fibrillation. Setting A cohort study conducted among atrial fibrillation patients using the UK Clinical Practice Research Datalink (March 2008-October 2014). Method New users of vitamin K antagonists, non vitamin K oral anticoagulants, low-dose aspirin, or combination therapy were followed from the date of first prescription to the date of death, as recorded in the UK datalink. Cox proportional hazard models estimated the hazard ratio (HR) of all-cause mortality for users of NOACs, aspirin, or combination use, as compared to vitamin K antagonist. Analyses were adjusted for confounders. Main outcome measure All-cause mortality. Results We identified 31,497 patients. Non vitamin K antocoagulant use (adjusted HR [aHR] = 1.42; 95% Confidence Interval [CI] 1.18-1.71) and aspirin use (aHR = 1.64; 95% CI 1.57-1.77) were both significantly associated with a higher mortality risk than use of vitamin K antagonists. The higher mortality risk for the non vitamin K anticoagulant use was observed in men (aHR = 1.72; 95% CI 1.25-2.36), but not in women (aHR = 1.28; 95% CI 0.92-1.79. Compared to vitamin K antagonists, mortality risk associated with the non vitamin K anticoagulants and aspirin use was significantly increased in patients with higher stroke risk (CHA 2 DS 2-VASc > 2). Conclusion Non vitamin K oral anticoagulants are associated with a higher risk on all-cause mortality, particularly in men and in patients with higher stroke risk.
NOACs were associated with a higher risk on gastrointestinal bleeding, particularly in women. The use of NOACs in patients who are vulnerable for this type of bleeding should be carefully considered. NOACs and VKAs are equally effective in preventing stroke. Aspirin was not effective in the prevention of stroke in AF.
The objective of the present study was to develop a dosing algorithm for ciprofloxacin based on both renal function and pathogen susceptibility in critically ill patients. In this observational prospective multicenter pharmacokinetic study, a total of 39 adult intensive care unit patients receiving ciprofloxacin were included. On two occasions a total of 531 samples of ciprofloxacin were collected. Renal function is a significant covariate on ciprofloxacin clearance. A dose of 400 mg every 12 hours was sufficient to reach the preestablished target of area under the curve (AUC) in relation to the minimum inhibitory concentration (MIC) (AUC/MIC) > 125 in patients with an estimated glomerular filtration rate (eGFR) < 130 mL/min and an infection caused by a pathogen with an MIC ≤ 0.125 mg/L. For patients with infections caused by pathogens with an MIC ≥ 0.5 mg/L and eGFR> 100 mL/min, doses up to 600 mg four times daily or more were estimated to be required. This study provides a new dosing algorithm for ciprofloxacin in critically ill patients. In order to achieve adequate target attainment, the dosing of ciprofloxacin should be based on renal function and the MIC of the causative pathogen. Higher doses than the standard licensed dose are necessary to obtain target attainment for less susceptible pathogens and patients with high renal clearance. In the setting of impaired renal function, a daily dose of 400 mg (which is currently recommended) will not result in adequate target attainment for less susceptible pathogens.
Objectives To describe the unbound and total flucloxacillin pharmacokinetics in critically ill patients and to define optimal dosing strategies. Patients and methods Observational multicentre study including a total of 33 adult ICU patients receiving flucloxacillin, given as intermittent or continuous infusion. Pharmacokinetic sampling was performed on two occasions on two different days. Total and unbound flucloxacillin concentrations were measured and analysed using non-linear mixed-effects modelling. Serum albumin was added as covariate on the maximum binding capacity and endogenous creatinine clearance (CLCR) as covariate for renal function. Monte Carlo simulations were performed to predict the unbound flucloxacillin concentrations for different dosing strategies and different categories of endogenous CLCR. Results The measured unbound concentrations ranged from 0.2 to 110 mg/L and the observed unbound fraction varied between 7.0% and 71.7%. An integral two-compartmental linear pharmacokinetic model based on total and unbound concentrations was developed. A dose of 12 g/24 h was sufficient for 99.9% of the population to achieve a concentration of >2.5 mg/L (100% fT>5×MIC, MIC = 0.5 mg/L). Conclusions Critically ill patients show higher unbound flucloxacillin fractions and concentrations than previously thought. Consequently, the risk of subtherapeutic exposure is low.
Background and Objective Previous pharmacokinetic (PK) studies of ciprofloxacin in intensive care (ICU) patients have shown large differences in estimated PK parameters, suggesting that further investigation is needed for this population. Hence, we performed a pooled population PK analysis of ciprofloxacin after intravenous administration using individual patient data from three studies. Additionally, we studied the PK differences between these studies through a post-hoc analysis. Methods Individual patient data from three studies (study 1, 2, and 3) were pooled. The pooled data set consisted of 1094 ciprofloxacin concentration-time data points from 140 ICU patients. Nonlinear mixed-effects modeling was used to develop a population PK model. Covariates were selected following a stepwise covariate modeling procedure. To analyze PK differences between the three original studies, random samples were drawn from the posterior distribution of individual PK parameters. These samples were used for a simulation study comparing PK exposure and the percentage of target attainment between patients of these studies. Results A two-compartment model with first-order elimination best described the data. Inter-individual variability was added to the clearance, central volume, and peripheral volume. Inter-occasion variability was added to clearance only. Body weight was added to all parameters allometrically. Estimated glomerular filtration rate on ciprofloxacin clearance was identified as the only covariate relationship resulting in a drop in inter-individual variability of clearance from 58.7 to 47.2%. In the post-hoc analysis, clearance showed the highest deviation between the three studies with a coefficient of variation of 14.3% for posterior mean and 24.1% for posterior inter-individual variability. The simulation study showed that following the same dose regimen of 400 mg three times daily, the area under the concentration-time curve of study 3 was the highest with a mean area under the concentration-time curve at 24 h of 58 mg•h/L compared with that of 47.7 mg•h/L for study 1 and 47.6 mg•h/L for study 2. Similar differences were also observed in the percentage of target attainment, defined as the ratio of area under the concentration-time curve at 24 h and the minimum inhibitory concentration. At the epidemiological cut-off minimum inhibitory concentration of Pseudomonas aeruginosa of 0.5 mg/L, percentage of target attainment was only 21%, 18%, and 38% for study 1, 2, and 3, respectively. Conclusions We developed a population PK model of ciprofloxacin in ICU patients using pooled data of individual patients from three studies. A simple ciprofloxacin dose recommendation for the entire ICU population remains challenging owing to the PK differences within ICU patients, hence dose individualization may be needed for the optimization of ciprofloxacin treatment.The members of the Dutch Antibiotic PK/PD are listed in acknowledgements section.
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